Synthesis,spectroscopic and spectrophotometric study of BODIPY appended crown ether sensor for ion detection

A novel fluoroionophore compound was synthesized from a boron dipyrromethene (BODIPY) fluorophore and 4′-formylbenzo-15-crown-5 ionophore groups. Photophysical properties of the BODIPY-crown compound were studied with UV–Vis and fluorescence spectroscopy. The effect of metalic cations (Li⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Ba²⁺, Al³⁺, Fe³⁺, Cu²⁺, Co²⁺, Zn²⁺, Ag⁺, Hg²⁺, Pb²⁺) on the absorption and fluorescence spectra of compound 2 was investigated. Blue shifts were detected in UV–Vis spectra upon addition of some metal ions (Al³⁺ > Fe³⁺ > Na⁺). At the same time, the emission intensity of this complex increased due to binding of Na⁺ ion to the benzo crown cavity. Additionally, a decrease in the intensity of the 630 nm emission peak and an increase in the intensity of the 570 nm emission peak was observed in the fluorescence emission spectra following addition of Al³⁺ and Fe³⁺ ions.     

New Benzo-15-Crown-5 Ethers Featuring Salicylic Schiff Base Substitutions – Synthesis, Complexes and Structural Study

Condensation reactions between 4'-formyl-5'-hydroxybenzo-15-crown-5and 2-aminopyridine, 2-amino-6-methylpyridine, 2-amino-4-methylpyridine or2-(aminomethyl)furan yielded the new laterally functionalized crown ethers1–4. The crown compounds 1–3 form crystalline 1:1 (Na⁺:ligand) complexes 1a–3a with sodium perchlorate. Ligands and complexes have been characterized by elemental analyses, IR, UV-Vis, ¹H-, ¹³C-NMR and mass spectra. The tautomeric equilibria (phenol-imine, O...H–N and keto-amine, O...H–N forms) have been systematically studied by using UV-Vis absorption spectra. The spectra of the ligands 1–4 and complexes 1a–3a were recorded in polar, non-polar, acidic, and basic media. In solutions of polar solvents, tautomeric interconversion of the Schiff base into the keto-amine form has been observed. A crystal structure [monoclinic, space group P2₁/c,a = 14.292(2), b = 9.449(6), c = 16.059(2) Å, = 114.20(1)°,V = 1978.4(13) ų, Z = 4 and D_x = 1.314 g cm^-3] shows that compound 4 is in the form of phenol-imine in solid state. There is a strong intramolecular [O–H...N 1.78(6), O...N 2.581(7), O–H 0.89(6) Å and N...H–O 148.4(5)°] hydrogen bond between the phenolic oxygen and imine nitrogen atoms. The C=N imine bond reveals a trans planar (1E) configuration. The molecules stack in columns parallel to the a/c plane of the unit cell.     

NOVEL N,S-SUBSTITUTED DIENES BY THE REACTION OF 2-NITROTHIOSUBSTITUTED HALODIENES AND PRIMARY AMINES

Mono(thio)substituted 1a–c gave compounds 3a–c and 5a with o-toluidin (2) and m-toluidin (4) in ether. Compounds 9a–c and 11a, b were obtained from the reaction of compounds 1a–c with p-fluorophenylamine (8) and p-fluorobenzylamine (10). Compounds 7a and 15c were obtained from the reaction of 1a and 1c with p-phenylendiamine (6) and o-phenylendiamine (14). Compound 13c was synthesized from the reaction of compound 1c with benzidine (2).     

N,S-, S-, S,S-, <S═O-, and < SO2-Substituted Dienes from Halo-1,3-Butadienes

Mono(thio)substituted dienes 1 gave 3a–g , 5 , and 7 with piperazine derivatives in dichloromethane. Hexachlorobutadiene 14 in a water-ethanol mixture in the presence of sodium hydroxide reacted with thiol 15 to give the mono(thio)substituted thioether 16 and di(thio)substituted thioether 17 . 18 was obtained from the reaction of 16 with m-CPBA in chloroform. 9 was obtained from the reaction of l,2,3,4,4-pentachloro-(1-2-hydroxyethylthio)-1,3- butadiene 8 with 47% HI, and 11 was synthesized from the reaction of 8 with concentrated H₂SO₄ and KBr. Compounds 9 and 11 gave in the reaction with m-CPBA in chloroform 10 , 12 , and 13 , respectively.     

Structural and spectroscopic characterization of 2,3-difluorobenzoic acid and 2,4-difluorobenzoic acid with experimental techniques and quantum chemical calculations

In this study, the molecular conformation, vibrational and electronic transition analysis of 2,3-difluorobenzoic acid and 2,4-difluorobenzoic acid (C7H4F2O2) were presented using experimental techniques (FT-IR, FT-Raman and UV) and quantum chemical calculations. FT-IR and FT-Raman spectra in solid state were recorded in the region 4000-400 cm(-1) and 4000-5 cm(-1), respectively. The UV absorption spectra of the compounds that dissolved in ethanol were recorded in the range of 200-800 nm. The structural properties of the molecules in the ground state were calculated using density functional theory (DFT) and second order M?ller-Plesset perturbation theory (MP2) employing 6-311++G(d,p) basis set. Optimized structure of compounds was interpreted and compared with the earlier reported experimental values. The scaled vibrational wavenumbers were compared with experimental results. The complete assignments were performed on the basis of the experimental data and total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. A study on the electronic properties, such as absorption wavelength, excitation energy, dipole moment and frontier molecular orbital energy, were performed by time dependent DFT (TD-DFT) approach. Based on the UV spectra and TD-DFT calculations, the electronic structure and the assignments of the absorption bands of steady compounds were discussed. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecules.     

Vortex-assisted magnetic solid phase extraction of Cd(II), Cu(II) and Pb(II) on the Nitroso–R salt impregnated magnetic Ambersorb 563 for their separation,preconcentration and determination by FAAS

A novel vortex-assisted magnetic solid phase extraction method followed by flame atomic absorption spectrometry was improved to separate, preconcentrate and determine the lead, copper and cadmium ions by using 1-Nitro-2-naphthol-3, 6-disulfonic acid disodium salt (Nitroso-R salt) impregnated magnetic Ambersorb-563 resin. The adsorbent was characterised by Fourier transform infrared spectra, BET surface analyser and scanning electron microscopy. The influences of various analytical parameters, such as pH value, type and volume of the eluent, sample volume, were optimised and the effects of potentially interfering ions were investigated. The analyte ions were quantitatively recovered at pH 7.0 on magnetic adsorbent and desorbed with a 2.0 M HNO₃ in 10% acetone as eluent. The detection limits were 1.4, 5.8 and 1.5 ng mL^?1 for Cd(II), Cu(II) and Pb(II), respectively. The method has been validated with analytically by the analysis certified reference materials and standard additions prior to application to determine metal ions in water samples.     

Photophysical and antimicrobial properties of new double-armed benzo-15-crown-5 ligands and complexes

Research on Chemical Intermediates - New double-armed crown ether ligands linked to pyridine derivatives have been synthesized and characterized. These macrocyclic ligands (1–5) have been...     

Synthesis,antimicrobial and thermal studies of nitropyridine-substituted double armed benzo-15-crown-5 ligands; alkali (Na+ and K+) and transition metal (Ag+) complexes; reduction of nitro compounds

Journal of Inclusion Phenomena and Macrocyclic Chemistry - Nitropyridine substituted double-armed benzo 15-crown-5 compounds (1–4) were synthesized by the reactions of...     

Secondary metabolites from the aerial parts of <Emphasis Type="Italic">Verbascum dudleyanum</Emphasis> and their biological activities

From the overground parts of Verbascum dudleyanum, six iridoid glycosides, aucubin, ajugol, catalpol, 6-O-α-L-rhamnopyranosylcatalpol, saccatoside, and 6-O-(3″-O-trans-p-coumaroyl)-α-L-rhamnopyranosylcatalpol, and two saponins, ilwensisaponin A and C, as well as a flavonoid, luteolin-7-O-β-glucopyranoside, together with an acetophenone glucoside, picein, were isolated. The structures of isolated compounds were elucidated by spectroscopic methods. These compounds showed biological acitivites. __________ Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 232–234, May–June, 2008.